From the abstract: "It is not the technology itself, but rather the image quality that seems crucial for reading."

In other words, it's what I've been saying for years. The important part is not the technology (eink vs. LCD, front-lit vs. backlit), but the resolution as in dots/pixels per inch. Eink has "fuzzy" pixels, and so gets an artificial boost to ppi despite being relatively low, though the new 1024x768 6" screens have finally cross the 200ppi barrier. Anything over 150ppi is comfortable for most people, which is why the iPad pre-retina display was bad for reading but the Nook Color was good.

Back light vs. front light vs. reflected light is a red herring.

Not a red herring... just because one thing is important doesn't eliminate contributory factors from other things... both pixel density and screen type are important...

Back in 2010 i purchased a kindle keyboard 3G as at the time most LCD screen where still relatively poor to read on ,but that's not the case these days as i found out when i purchased a nexus 7.

Dew to the much higher screen resolution + DPI + the ability to dim the screen to suit the light conditions you can comfortably read off most of these tablets as i have read books on my nexus 7 for 8+ hours strait per day on some occasions and i suffered no problems to date .

Also most reading Apps have a night viewing - black paper with white writing and well as having yet another dimming feature in the app can help even more.

There's a very large gap between what today's tablets can do that Eink's cant to do so i gave trying to find a replacement for my kindle and im glad i did.Maybe in the future i will buy a CHEAP multi-format Eink that wont tie me down like the kindle keyboard did but until then im happy with my nexus 7.

One of the best ebook reader Apps out there is MOON+READER PRO for any android tablet as it covers the most common formats and has so many feature to go crazy with.You can also access the dropbox streaming service as i do and upload your whole collection of ebooks if you desire and read your books on any of your reading devices as they will be all be synced.

I think the main difference is the way I read. When I read a book I take off my glasses and hold the device quite close to my face. When use a tablet for browsing, reading the newspaper, or watch a video I hold it much farther away. With my laptop the distance is even greater. And the closer I get to my eyes, the less comfortable I feel with LCD screens.

I think the main difference is the way I read. When I read a book I take off my glasses and hold the device quite close to my face. When use a tablet for browsing, reading the newspaper, or watch a video I hold it much farther away. With my laptop the distance is even greater. And the closer I get to my eyes, the less comfortable I feel with LCD screens.

This is why dpi is so important. Your laptop screen most likely has a resolution around 100dpi (a 1080p 15" screen is only 140-ish dpi). That's way too low resolution to read comfortably on, especially if you're holding it right up to your face. An iPhone 4/4S/5, iPad 3, Galaxy III S, Nexus 7, etc (basically any modern high-end phone or tablet) will have dpis well above twice that of your PC, possibly even three times or more.

Start with a high quality device, add a high quality reader (I like Aldiko on Android), switch to "night mode" (white text on black background), and adjust brightness and font size as needed and you may find LCDs a lot more comfortable to read on.

This is why dpi is so important. Your laptop screen most likely has a resolution around 100dpi (a 1080p 15" screen is only 140-ish dpi). That's way too low resolution to read comfortably on, especially if you're holding it right up to your face. An iPhone 4/4S/5, iPad 3, Galaxy III S, Nexus 7, etc (basically any modern high-end phone or tablet) will have dpis well above twice that of your PC, possibly even three times or more.

Start with a high quality device, add a high quality reader (I like Aldiko on Android), switch to "night mode" (white text on black background), and adjust brightness and font size as needed and you may find LCDs a lot more comfortable to read on.

My wife's iPhone 4, at any brightness setting, is better than backlit devices with lower resolution, but can't hold a candle to my low resolution Kindle DX. And night-mode? No, that is extremely uncomfortable. Sepia works best for me.

Since the research did not include paper and ink, or older displays, it is impossible to tell whether displays have improved in general (as far as eye fatigues goes), or e-ink isn't (yet) very helpful, or some combination of factors. That is assuming the results hold up; when there is apparent contradiction with previous work, then more work needs to be done to resolve the contradiction.

This is why dpi is so important. Your laptop screen most likely has a resolution around 100dpi (a 1080p 15" screen is only 140-ish dpi). That's way too low resolution to read comfortably on, especially if you're holding it right up to your face. An iPhone 4/4S/5, iPad 3, Galaxy III S, Nexus 7, etc (basically any modern high-end phone or tablet) will have dpis well above twice that of your PC, possibly even three times or more.

Start with a high quality device, add a high quality reader (I like Aldiko on Android), switch to "night mode" (white text on black background), and adjust brightness and font size as needed and you may find LCDs a lot more comfortable to read on.

If you hold a backlit device closer to your eyes, you will get more eyestrain from looking into a light source. The further you have it away, the more the light will scatter. The closer you keep it, the more light will fall in your eyes.

Yes, resolution does matter, a lot. I had a cheap 800x480 7" reader. Didn't have that much trouble reading on it, but I noticed a huge difference when I switched to my higher resolution Flyer....

And I get eyestrain when I read on my e-ink device, unless I'm in a well-lit area.

One important bit: The test was of the Sony PRS-600 vs. original iPad in normal indoor lighting only.

Thanks for the info.

Kinda nullify's the test. I used to read on a 600 in normal lighting and I got eye-strain (red eyes) and head-aches. I had to get rid of it. Now I read on a 650 usually with a light. The two experiences are very different. If reading on an (original) ipad is like reading on a 600 without a light, it must be dreadful.